Hi, 

I have 2 models:

class ProjectTask (models.Model): # project_task.py

_inherit = "project.task" 

    task_line_ids = fields.One2many('project.task.line','task_id',string="Articles")

state = fields.Selection((('draft','Draft'),('open','In progress'),('done','Done'),('cancel','Cancelled')), default = 'draft', string='Status', required="True")

  @api.multi

def action_draft(self):

return self.write({'state': 'draft'})

@api.multi

def action_open(self):

return self.write({'state': 'open'})

@api.multi

def action_done(self):

return self.write({'state': 'done'})

@api.multi

def action_cancel(self):

return self.write({'state': 'cancel'})

class ProjectTaskLine(models.Model):

_name = 'project.task.line'

quantity = fields.Float("Quantity")

price_unit = fields.Float("Unit Price")

product_id = fields.Many2one('product.product', string='Article')

task_id = fields.Many2one('project.task')

progress = fields.Float('Progress') 

in the project_task.xml

 <xpath expr="//form/sheet/notebook/page[@name='description_page']" position="before">

<page string="Articles">

<field name="task_line_ids">

<tree string="Batchs Order Lines" editable="bottom">

<field name="product_id" />    

<field name="quantity"/>

<field name="price_unit"/>

<field name="progress" attrs="{'invisible': [('state','in','draft'])]}"/>

</tree>

</field>

</page>

</xpath>

I want to hide the column "progress" in the o2m field when the state = 'draft',but i get this message error : Uncaught Error: QWeb2 - template['ListView.row']: Runtime Error: Error: Unknown field state in domain [["state","in","draft"]]

How can i do to solve it please ?

Thanks